docs: def serve_forever(self, poll_interval=0.5):
          """ Wait for incomming requests. """
          self.serial_port.timeout = poll_interval
  
          while not self._shutdown_request:
              try:
                  self.serve_once()
              except (CRCError, struct.error) as e:
                  log.error('Can\'t handle request: {0}'.format(e))
              except (SerialTimeoutException, ValueError):
                  pass